print("")
s= input()
s1 = ''

for char in s:
    if char == "(":
        s1 += char
    if char == ")":
        if len(s1)>0:
            if s1[len(s1)-1]== '(':
                s1=s1[:-1]
for char in s:
    if char == "{(":
        s1 += char
    if char == "}":
        if len(s1)>0:
            if s1[len(s1)-1]== '{':
                s1=s1[:-1]
for char in s:
    if char == "[":
        s1 += char
    if char == "]":
        if len(s1)>0:
            if s1[len(s1)-1]== '[':
                s1=s1[:-1]
for char in s:
    if char == "<":
        s1 += char
    if char == ">":
        if len(s1)>0:
            if s1[len(s1)-1]== '<':
                s1=s1[:-1]
if len(s1)==0:
    print("верная")
else:
    print("неверная")